/Engine/Source/Runtime/GeometryCore/Public/CompGeom/ExactPredicates.h
value w/ sign indicating whether the normal of line AB is facing Direction (and 0 if parallel) (i.e. the sign of -PerpCW(B-A) dot Dir)
namespace UE { namespace Geometry { namespace ExactPredicates { template<typename RealType> RealType UE::Geometry::ExactPredicates::Facing2 ( const [TVector2](API\Runtime\Core\Math\TVector2)< RealType > & A, const [TVector2](API\Runtime\Core\Math\TVector2)< RealType > & B, const [TVector2](API\Runtime\Core\Math\TVector2)< RealType > & Direction ) } } }